add polymorphic association loader

lib/philomena/notifications/notification.ex

@@ -11,6 +11,9 @@ defmodule Philomena.Notifications.Notification do
     field :actor_child_id, :integer
     field :actor_child_type, :string
 
+    field :actor, :any, virtual: true
+    field :actor_child, :any, virtual: true
+
     timestamps(inserted_at: :created_at)
   end
 

lib/philomena/polymorphic.ex

@@ -0,0 +1,53 @@
+defmodule Philomena.Polymorphic do
+  alias Philomena.Repo
+  import Ecto.Query
+
+  @classes %{
+    "Channel" => Philomena.Channels.Channel,
+    "Comment" => Philomena.Comments.Comment,
+    "Commission" => Philomena.Commissions.Commission,
+    "Conversation" => Philomena.Conversations.Conversation,
+    "Filter" => Philomena.Filters.Filter,
+    "Forum" => Philomena.Forums.Forum,
+    "Gallery" => Philomena.Galleries.Gallery,
+    "Image" => Philomena.Images.Image,
+    "LivestreamChannel" => Philomena.Channels.Channel,
+    "Post" => Philomena.Posts.Post,
+    "Topic" => Philomena.Topics.Topic,
+    "User" => Philomena.Users.User
+  }
+
+  # Deal with Rails polymorphism BS
+  def load_polymorphic(structs, associations) when is_list(associations) do
+    Enum.reduce(associations, structs, fn asc, acc -> load_polymorphic(acc, asc) end)
+  end
+
+  def load_polymorphic(structs, {name, {id, type}}) do
+    modules_and_ids =
+      structs
+      |> Enum.group_by(& &1[type], & &1[id])
+
+    loaded_rows =
+      modules_and_ids
+      |> Map.new(fn
+        {nil, _ids} ->
+          {nil, []}
+
+        {type, ids} ->
+          rows =
+            @classes[type]
+            |> where([m], m.id in ^ids)
+            |> Repo.all()
+            |> Map.new(fn r -> {r.id, r} end)
+
+          {type, rows}
+      end)
+
+    structs
+    |> Enum.map(fn struct ->
+      row = loaded_rows[struct[type]][struct[id]]
+
+      %{struct | name => row}
+    end)
+  end
+end

lib/philomena/reports/report.ex

@@ -18,6 +18,8 @@ defmodule Philomena.Reports.Report do
     field :reportable_id, :integer
     field :reportable_type, :string
 
+    field :reportable, :any, virtual: true
+
     timestamps(inserted_at: :created_at)
   end